class_docstr: This class has pool interface but performs all work in calls to get_results. It is sometimes convenient
  to substitute a real pool with this dummy implementation.
  
  Found this class useful when profiling worker code. When on a separate thread, the worker code was not observable
  (out of the box) by the profiler
code: def join(self):
      pass
  
file_path: petastorm/petastorm/workers_pool/dummy_pool.py
imports: from time import sleep
  from petastorm.workers_pool import EmptyResultError
label_desc: Use image node_id 6 for calling the DummyPool obj's underlying member method code with example usage: obj.join() without return types